[comp.lang.lisp.franz] Looking for help with serial streams

tg@gt-cmmsr.GATECH.EDU (T. Govindaraj) (11/25/88)

One of our software projects, a "real-time" simulation of a satellite
command and control system, requires communication between unix machines
and a Mac II. (The Unix machine, a VAX or a Sun 3, has the simulation
running in C and the Mac II has an application running in Allegro Common
Lisp.) Data from the unix machine is read by the Mac, which uses it to
compute the next action etc. When the program on the Mac II was Smalltalk80
we had no problems with communication.

We are using serial-streams.lisp, a file in the library of version 1.1
of Allegro Common Lisp from Coral. (The current version, 1.2, does not
include this file.) This file has scant documentation; whatever is there
is not that difficult to follow.

We encounter problems when we try to send "large" files that have more
than a few hundred characters. We have tried sending at speeds ranging
from 1200 baud to 9600 baud. When the file is large, on the unix machine,
characters are lost randomly. (It may not actually be random, but it
appears that way.) The files are sent from the unix machine to the Mac II.

It appears that Xon/Xoff is not set properly and/or the buffer size is
too small on the (Mac) input side. Since we are not Mac wizards (neither
my colleague nor I, the faculty-types, nor the student-types) we are
at a loss as to what to do. Of course one possibility is to control the
size of the file that goes to the Mac by splitting the data into smaller
packets. However, this is not a clean solution.

Any pointers as to how this problem can be solved will be greatly appreciated.
Some of us do know about traps and how to use them, if only we can figure
out what to use. Inside Macintosh, Vol. 2, doesn't seem to be of much
help, at least at the level we know such things.

If you know of nay means by which we can send large files from unix
machines to Mac II running Allegro Common Lisp, we would appreciate all
your help. Thank you.

govind

-- 
T. Govindaraj

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